The Computation lyrics

For the first twenty years since yesterday
I scarce believed thou couldst be gone away;
For forty more I fed on favors past,
And forty on hopes that thou wouldst they might last.
Tears drowned one hundred, and sighs blew out two,
A thousand, I did neither think nor do,
Or not divide, all being one thought of you,
Or in a thousand more forgot that too.
Yet call not this long life, but think that I
Am, by being dead, immortal. Can ghosts die?